1. Field of the Invention
The present invention relates to a display device generally, and more particularly, to a flat fluorescent lamp and a display device having the same, by which a luminance can be improved and a driving voltage can be reduced.
2. Description of the Related Art
Recent developments in semiconductor technology permit the manufacture of display devices having smaller size, lighter weight, and better performance than predecessor cathode ray tube (CRT) display devices, but the need for improved and more reliable illumination sources has increased accordingly.
Among various kinds of flat display devices, a liquid crystal display (hereinafter referred to as an “LCD”) is highlighted as a next-generation display device capable of overcoming shortcomings of a conventional cathode ray tube (CRT) display because the LCD can be manufactured smaller, lighter, and with lower power consumption than a CRT display. For these reasons, today, most data processing devices employ an LCD device.
In a typical LCD device, molecular orientations of liquid crystal cells are changed by a voltage applied thereto. Such changes of the molecular orientations result in changes of optical properties, such as birefringence, optical rotation, dichroism, and light scattering in luminescent liquid crystal cells, and thereby, the light transmitting the liquid crystal cell is modulated so that a desired image data can be visually perceived by a user.
Since the LCD panel is a non-emissive element, a typical LCD device includes a light source such as a backlight unit for supplying the light from the bottom of the liquid crystal panel. A large-sized LCD device such as a digital TV usually employs a plurality of lamps as the backlight unit. As a result, a plurality of parts and components need to be provided and assembled together, thereby complicating the manufacturing process. Furthermore, the thickness of the backlight unit may be increased to prevent breakage of the lamps due to external impacts. However, this added protection tends to increase the overall thickness of the LCD device itself.
In order to solve such problems, flat fluorescent lamps have been developed. In such lamps, fluorescent gases are injected into the inside of the lamp and discharged to emit light. A drawback of fluorescent lamps is that if electrodes are provided in the outside surface of a glass substrate, a thick glass substrate of about 0.7 mm to about 2.0 mm needs to be used as a dielectric layer. This range of thickness produces a large voltage drop in the glass substrate. To compensate this, a high voltage must be supplied to the flat fluorescent lamp. Nevertheless, a desired luminance cannot be guaranteed.
In an attempt to solve such problems, another type of flat fluorescent lamp has been developed. In the second type of flat fluorescent lamp, electrodes are provided in the inside surface(s) of the glass substrate, and dielectric layers are formed on the electrodes. This configuration permits the flat fluorescent lamp to be discharged using a reduced discharge voltage. However, due to the discharge characteristics of this type of flat fluorescent lamp, its luminance remains less than satisfactory.
A solution is needed that provides an improved flat fluorescent lamp having improved luminance and reduced driving voltage, as well as an LCD incorporating the same.